1. Field of the Invention
The present invention relates to a composition, a resist pattern-forming method, a compound, a method for production of the compound and a polymer.
2. Discussion of the Background
In the field of microfabrication typified by production of integrated circuit devices, chemically amplified resists have been conventionally used. In the chemically amplified resists, irradiation with, for example, a radioactive ray having a short wavelength such as an excimer laser beam generates an acid at light-exposed sites to cause a difference in rates of dissolution in an alkaline developer solution between light-exposed sites and light-unexposed sites by a reaction by way of the acid as a catalyst, thereby forming a resist pattern on a substrate.
In such chemically amplified resists, as a method for forming a finer resist pattern, utilization of a liquid immersion lithography process (liquid immersion lithography) is expanding in which exposure is conducted while allowing a space between a lens and a resist film to be filled with a liquid immersion media such as, for example, pure water or a fluorine-based inert liquid. The liquid immersion lithography process allows for an increase in numerical aperture (NA) of the lens, and further provides advantages that a depth of focus is hardly decreased and additionally a high resolution can be achieved even under increased NAs, and the like.
On the other hand, in the resist pattern formation by the liquid immersion lithography process, it is required to improve a scan speed, while inhibiting pattern defects attributed to elution of a component from the resist film and/or beads of a liquid remaining on the surface of the resist film. As a technique for meeting the requirements, it is proposed to provide an upper layer film for liquid immersion lithography between the resist film and a liquid immersion medium (see, Japanese Unexamined Patent Application, Publication No. 2006-91798 and PCT International Publication Nos. WO 2008/47678 and WO 2009/41270). These Patent Documents disclose that: the upper layer film for liquid immersion lithography is provided on the resist film using a water-insoluble and alkali-soluble polymer; during the liquid immersion lithography, inhibition of the elution of the resist film component and the like is achieved based on water repellency exhibited by the upper layer film for liquid immersion lithography; and additionally, in a subsequent step of development, the upper layer film for liquid immersion lithography is peeled from the surface of the resist film by dissolving the upper layer film for liquid immersion lithography in a developer solution.
In addition, recently, lithography in which an EUV, an electron beam or the like (hereinafter, may be also referred to as “EUV and the like”) having a shorter wavelength than the excimer laser beam is used has been investigated as another method for forming a finer pattern (see Japanese Unexamined Patent Application, Publication Nos. 2006-171440, 2011-16746 and 2010-204634). However, in the case of the lithography carried out using the EUV is the like, an exposure needs to be carried out under vacuum, and therefore a reduction of outgassing from the resist film is demanded. Accordingly, as a technique for meeting the demand, it has been proposed to provide an upper layer film for EUV and the like that covers the surface of the resist film. Also in the upper layer film of this type, suppression of outgassing or the like during, for example, an exposure to the EUV and the like is expected to be enhanced by the water repellency exhibited by the upper layer film; however, the upper layer film needs to be peeled from the surface of the resist film in a subsequent development step by dissolving the upper layer film in a developer solution.